Adaptive out of service scanning

ABSTRACT

A method for selecting an out of service (OOS) scan mode for a wireless communication device is provided. The method can include the wireless communication device detecting occurrence of an OOS condition; setting a displacement threshold in response to the OOS condition; determining a displacement magnitude indicative of a distance traveled by the wireless communication device during the OOS condition; determining whether the displacement magnitude exceeds the displacement threshold; using a first scan mode to scan for network coverage in an instance in which it is determined that the displacement magnitude exceeds the displacement threshold; and using a second scan mode to scan for network coverage in an instance in which it is determined that the displacement magnitude does not exceed the displacement threshold. The first scan mode can have a greater scan frequency than the second scan mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to both U.S. Provisional PatentApplication No. 61/662,299, filed on Jun. 20, 2012, and U.S. ProvisionalPatent Application No. 61/662,328, filed on Jun. 20, 2012, the contentsof both of which are incorporated herein in their entirety by reference.

FIELD OF THE DESCRIBED EMBODIMENTS

The described embodiments relate generally to wireless communicationsand more particularly to adaptive out of service (OOS) scanning

BACKGROUND

During the course of wireless communication device usage, the wirelesscommunication device can loose connectivity to a cellular network,resulting in an out of service (OOS) condition. Loss of connectivity canbe due to a variety of reasons. In some cases, loss of connectivity canresult from the wireless communication device moving to an area withlimited or no coverage. As another example, loss of connectivity canresult from the wireless communication device experiencing a temporaryloss of reception due to a fading condition, such as can result from ashadowing effect in an urban location, such as when a wirelesscommunication device is located in an elevator.

When a wireless communication device experiences an OOS condition as aresult of losing network connectivity, the wireless communication devicetypically scans for network service to reacquire network connectivity.In many cases, the wireless communication device can repeatedly scanunsuccessfully for networks and cause battery depletion, especially whenthe wireless communication device is in an area where there is nocoverage. Some wireless communication devices attempt to reduce batterydepletion resulting from unsuccessful scan attempts by applying aback-off algorithm in which the intervals between scan attempts aregradually increased over time. However, application of a back-offalgorithm to reduce battery depletion can have a negative tradeoff, aswhen the wireless communication device moves into a location wherenetwork coverage exists, there can be an undesirable delay inre-establishing network connection due to the increased interval betweenscan attempts.

SUMMARY OF THE DESCRIBED EMBODIMENTS

Some example embodiments disclosed herein provide for adaptive OOSscanning whereby a wireless communication device can be configured toselect an aggressiveness of a scanning mode to apply when scanning fornetwork coverage in an OOS condition based at least in part on thelikelihood that the device will discover network coverage. In thisregard, a wireless communication device in accordance with some exampleembodiments can apply an aggressive scan mode with a greater frequencyof scan attempts (e.g., smaller intervals between scan attempts) in asituation in which the device is more likely to reacquire networkservice and can apply a non-aggressive scan mode having a lowerfrequency of scan attempts (e.g., larger intervals between scanattempts) in a situation in which the device is less likely to reacquirenetwork service.

More particularly, the wireless communication device of some exampleembodiments can be configured to set a displacement threshold defining athreshold a displacement threshold defining a threshold minimum distanceto be traveled by the device during the OOS before an aggressive scanmode with a higher scanning frequency is applied based on conditionsobserved by the wireless communication device that can be indicative ofhow far the wireless communication device may have to travel beforereentering an area of network coverage such that it is likely thatnetwork coverage can be reacquired. If the device has not traveled atleast the threshold distance during the OOS condition, then anon-aggressive scan mode with a lower scanning frequency can be used.After the device of such example embodiments has traveled the thresholddistance during the OOS condition, the device can switch to a moreaggressive scan mode with an increased frequency of scan attempts.

This Summary is provided merely for purposes of summarizing some exampleembodiments of the invention so as to provide a basic understanding ofsome aspects of the invention. Accordingly, it will be appreciated thatthe above described example embodiments are merely examples and shouldnot be construed to narrow the scope or spirit of the invention in anyway. Other embodiments, aspects, and advantages of the invention willbecome apparent from the following detailed description taken inconjunction with the accompanying drawings which illustrate, by way ofexample, the principles of the described embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The described embodiments and the advantages thereof may best beunderstood by reference to the following description taken inconjunction with the accompanying drawings. These drawings are notnecessarily drawn to scale, and in no way limit any changes in form anddetail that may be made to the described embodiments by one skilled inthe art without departing from the spirit and scope of the describedembodiments.

FIG. 1 illustrates an example generic non-adaptive cellular searchpattern.

FIG. 2 illustrates example problems that can result from use of thegeneric non-adaptive cellular search pattern of FIG. 1 in out of serviceconditions.

FIG. 3 illustrates an example wireless communication system inaccordance with some example embodiments.

FIG. 4 illustrates a block diagram of an apparatus that can beimplemented on a wireless communication device in accordance with someexample embodiments.

FIG. 5 illustrates an example of large scale pathloss and shadowing vs.small scale fading effect on received power levels.

FIG. 6 illustrates provisioning of location-coverage mapping informationin accordance with some example embodiments.

FIG. 7 illustrates a flowchart according to an example method foradaptive out of service scanning according to some example embodiments.

FIG. 8 illustrates a flowchart according to another example method foradaptive out of service scanning according to some example embodiments.

FIG. 9 illustrates a flowchart according to an example method foradaptive out of service scanning based on a rate of degradation in areceived signal quality prior to an out of service condition accordingto some example embodiments.

FIG. 10 illustrates a flowchart according to an example method foradaptive out of service scanning based on location-coverage mappinginformation according to some example embodiments.

FIG. 11 illustrates a state diagram for selecting between application ofa deterministic mode and a statistical mode for selecting an out ofservice scan mode according to some example embodiments.

FIGS. 12A and 12B illustrate a flowchart according to an example methodfor adaptive out of service scanning according to some exampleembodiments.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

When a wireless communication device experiences an OOS condition, thereis always a tradeoff between quickly reacquiring network service andreducing the level of battery consumption. In this regard, whileperforming more frequent scans can result in the device reacquiringnetwork service more quickly, increasing the scanning frequency resultsin increased battery consumption. In contrast, while reducing thescanning frequency reduces the level of battery consumption, reducedscanning frequency can result in slower reacquisition of network serviceby the device. The balance between reacquiring network service asquickly as possible while avoiding unnecessary scans that result inexcess battery consumption is very crucial for device performance.

Current search algorithms applied during OOS conditions utilize ageneric non-adaptive search pattern, such as that illustrated in FIG. 1.The generic non-adaptive search pattern includes performance of aninitial continuous scan period for a continuous scan period spanningfrom detection of the OOS condition to time T_initial_scan 102, asillustrated in FIG. 1. After the initial continuous scan period, thedevice applies a back-off algorithm and performs scans at predefinedtime intervals, such as T_interval 104. After each scan attempt (orafter repeatedly scanning with a certain interval, such as T_interval104, N_rep times), the scan interval is increased until converging to amaximum scan interval, such as T_interval_max 106, which is used by thedevice until it finds cellular network coverage. Thus, in the example ofFIG. 1, the initial T_interval 104 that is used after the initialcontinuous scan period is completed at T_initial_scan 102 isprogressively increased by way of a backoff mechanism with each scanattempt performed after N_rep scans until converging to T_interval_max106.

The generic non-adaptive cellular search pattern illustrated in FIG. 1does not take into consideration the user and device specificconditions, as illustrated in FIG. 2, and can present several problemswhen used to perform a search in an OOS condition. In this regard, thedevice can be in a coverage hole during the OOS condition. Thus, if thedevice does not move for a period during the OOS condition, any scanattempts can be unsuccessful and can result in excess battery condition.In the example of FIG. 2, the device remains substantially in the samelocation from the beginning of the OOS condition until time t_mobility202. Thus, as illustrated by the period 204, the frequent scan attemptsperformed prior to t_mobility 202 in accordance with the genericnon-adaptive search pattern can be unsuccessful and result in excessbattery consumption by the device, as the device remains in an OOSregion while substantially stationary.

After a period of device mobility 206, the device reenters an area withnetwork coverage at time t_coverage 208. However, as a result of theincreased intervals between scan attempts pursuant to the back-offmechanism of the generic non-adaptive search pattern applied during theperiod 204 when the device was not mobile, the device does not perform ascheduled scan after reentering network coverage until time t_recovery210. Thus, even after the device reenters network coverage, OOS recoverycan be delayed for the delay period 212 between t_coverage 208 andt_recovery 210, which can have a duration of anywhere between[0-T_interval_max] depending on when t_coverage 208 occurs relative tothe previous scan attempt. User experience can accordingly suffer due todelayed scanning for network coverage after reentering an area ofcoverage when using a generic non-adaptive search pattern, asillustrated by the delay period 212 in the example of FIG. 2.

Some example embodiments provide systems, methods, apparatuses, andcomputer program products for performing adaptive OOS scanning, whichaddress deficiencies resulting from usage of conventional genericnon-adaptive search patterns, such as illustrated in and described withrespect to FIG. 1 and FIG. 2. For example, adaptive OOS scanning inaccordance with some example embodiments can reduce the incidence ofexcess battery consumption and delayed OOS recovery that result fromusage of conventional generic non-adaptive search patterns.

In this regard, rather than using the same predefined time interval(s)for scanning during OOS conditions, a wireless communication device inaccordance with some example embodiments can be configured to adaptivelyselect a scan mode to apply based at least in part on a likelihood thatnetwork service can be reacquired and/or based on user triggered eventsindicative of whether a user desires network service during the OOScondition. More particularly, in accordance with some exampleembodiments, a more aggressive scan mode (e.g., a higher scan frequencyand/or smaller interval(s) between scan attempts) can be applied inscenarios in which the device is more likely to reacquire networkservice and/or in which the user demands service so as to avoid delayedOOS recovery and improve user experience in such scenarios. Similarly,in scenarios in which the device is less likely to reacquire serviceand/or when the user does not demand service, a less aggressive, orpassive, scan mode (e.g., lower scan frequency and/or larger interval(s)between scan attempts) can be applied so as to avoid unnecessary batteryconsumption that would otherwise result from unnecessary/failed scanattempts in such scenarios.

As will be described further herein below, a variety of factors can beutilized by a wireless communication device in accordance with variousexample embodiments to select the scan mode to use in an OOS condition.For example, the likelihood of reacquiring network service can beevaluated based at least in part on device location; device mobilityconditions, such as device position, velocity, distance traveled afteroccurrence of the OOS condition, and/or other mobility factors;date/time of the OOS condition; pre-known harvested location data forcellular coverage with a certain proximity to the region of OOScondition (e.g., location-coverage mapping information); and/or thelike. User triggered events that can be used to determine whether thedevice user desires network service during the OOS condition can, forexample, include touch screen events; an input to a keypad; user attemptto make a call; attempt to make an emergency call; a pending textmessage, such as a short message service (SMS) message, multimediamessaging service (MMS) message, and/or other text message; and/or otheruser input that can be indicative of a user desire for and/or useraction requiring network service. As will be appreciated from furtherdiscussion of various embodiments herein below, the user events anddevice condition metrics which can be utilized in adaptive scan mode areconfigurable and the decision on a scan mode to apply can be based on acombination of various events/metrics.

FIG. 3 illustrates an example wireless communication system 300 inaccordance with some example embodiments. The system 300 can include awireless communication device 302, which, by way of non-limitingexample, can be embodied as a cellular phone, such as a smart phonedevice, a tablet computing device, a laptop computing device, or othercomputing device configured to access a cellular and/or other wirelessnetworks.

The system 300 can further include one or more network access points304. A network access point 304 can be embodied as any access point thatcan be used to access a wireless network. Thus, for example, inembodiments in which the system 300 includes one or more cellularnetworks, which the wireless communication device 302 can be configuredto access, a network access point 304 can be a cellular base station,such as a base transceiver station, node B, evolved node B (eNB), homeeNB, and/or other cellular base station. In embodiments in which thesystem 300 includes a network access point(s) 304 that is embodied ascellular base station, the network access point(s) 304 can be configuredto provide access to a cellular network(s) using any cellular radioaccess technology (RAT). Thus, by way of non-limiting example, thesystem 300 can include a network access point 304 configured to provideaccess to a cellular network using a fourth generation (4G) cellularRAT, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), and/or thelike; a third generation (3G) cellular RAT, such as Wideband CodeDivision Multiple Access (WCDMA) or other Universal MobileTelecommunications System (UMTS) RAT, a CDMA2000 RAT, and/or the like; asecond generation cellular (2G) RAT, such as Global System for MobileCommunications (GSM); and/or other present or future developed cellularRAT.

It will be appreciated, however, that embodiments disclosed herein arenot limited to application within cellular networks, but can also beapplied to OOS scanning for wireless networks using radio accesstechnologies (RATs) other than cellular RATs. For example, someembodiments can be applied to OOS scanning for wireless local areanetworks (WLANs), such as, by way of example, WLANs implementing anInstituted of Electrical and Electronics Engineers (IEEE) 802.11standard. As such, it will be appreciated that a network access point304 can be a type of wireless network access point other than a cellularbase station, such as a wireless router for a WLAN, in embodiments inwhich the system 300 includes a non-cellular wireless network(s) forwhich OOS scanning can be performed in addition to or in lieu of acellular network(s). It will be further appreciated that where exampleembodiments are described with respect to OOS scanning for cellularnetworks, techniques and methodologies described with respect to thoseembodiments can be applied mutatis mutandis to OOS scanning for otherwireless networking technologies within the scope of the disclosure.

The wireless communication device 302 can be configured to access awireless network via a network access point 304. When the wirelesscommunication device 302 is in a mobility state, the wirelesscommunication device 302 can transition between network access points.The wireless communication device 302 can encounter an OOS condition inan instance in which the device loses and/or otherwise cannot establisha connection to a network access point 304. For example, the wirelesscommunication device 302 can experience an OOS condition in an instancein which, due to mobility, the wireless communication device 302 entersan area known as a coverage gap, which is not within sufficient range ofa network access point 304 to receive network coverage. As a furtherexample, the wireless communication device 302 can experience an OOScondition in an instance in which the wireless communication device 302is within signaling range of a network access point 304, but at leasttemporarily loses signal from the network access point 304 due to ashadowing condition that can be caused by an obstruction in the signalpath, such as can occur if the wireless communication device 302 is inan elevator.

When the wireless communication device 302 experiences an OOS condition,the wireless communication device 302 can be configured to scan fornetwork coverage. In some instances OOS scanning for network coveragecan, for example, include scanning for the same network/RAT that thewireless communication device 302 was using before experiencing the OOScondition. Additionally or alternatively, in some instances, OOSscanning can include scanning for an alternative network(s)/RAT(s) inaddition to or in lieu of the network/RAT that the wirelesscommunication device 302 was using before experiencing the OOScondition. As will be described further herein below, the wirelesscommunication device 302 can be configured to perform adaptive scanningin an OOS condition based at least in part on conditions observed by thedevice, such as a likelihood that the device can reacquire networkservice, user input to the device indicative of whether the user wantsto utilize a service or function needing network service, and/or otherconditions.

In some example embodiments, the system 300 can optionally furtherinclude a coverage information provisioning apparatus 306. Inembodiments including a coverage information provisioning apparatus 306,the coverage information provisioning apparatus 306 can, for example, bea network-accessible entity that can be operated by a network carrier, amanufacturer of the wireless communication device 302, and/or otherservice provider. The coverage information provisioning apparatus 306can, for example, be embodied as a one or more servers, a cloudcomputing infrastructure, or other computing entity. As will bedescribed further herein below, the coverage information provisioningapparatus 306 can be a network entity that in some example embodimentscan collect data regarding network coverage in various locations and canform and store location-coverage mapping information indicative ofwhether network coverage is available in respective locations. Inembodiments including a coverage information provisioning apparatus 306,location-coverage mapping information that can be maintained by thecoverage information provisioning apparatus 306 can be provisioned tothe wireless communication device 302 and can be used by the wirelesscommunication device 302 to evaluate a likelihood of reacquiring networkservice during an OOS condition and to select an appropriate scan modegiven the device's location, as will be further described herein below.

FIG. 4 illustrates a block diagram of an apparatus 400 that can beimplemented on a wireless communication device 302 in accordance withsome example embodiments. In this regard, when implemented on acomputing device, such as wireless communication device 302, apparatus400 can enable the computing device to operate within the system 300 inaccordance with one or more example embodiments. It will be appreciatedthat the components, devices or elements illustrated in and describedwith respect to FIG. 4 below may not be mandatory and thus some may beomitted in certain embodiments. Additionally, some embodiments caninclude further or different components, devices or elements beyondthose illustrated in and described with respect to FIG. 4.

In some example embodiments, the apparatus 400 can include processingcircuitry 410 that is configurable to perform actions in accordance withone or more example embodiments disclosed herein. In this regard, theprocessing circuitry 410 can be configured to perform and/or controlperformance of one or more functionalities of the apparatus 400 inaccordance with various example embodiments, and thus can provide meansfor performing functionalities of the apparatus 400 in accordance withvarious example embodiments. The processing circuitry 410 can beconfigured to perform data processing, application execution and/orother processing and management services according to one or moreexample embodiments.

In some embodiments, the apparatus 400 or a portion(s) or component(s)thereof, such as the processing circuitry 410, can include one or morechipsets, which can each include one or more chips. The processingcircuitry 410 and/or one or more further components of the apparatus 400can therefore, in some instances, be configured to implement anembodiment on a single chip or chipset. In some example embodiments inwhich one or more components of the apparatus 400 are embodied as achipset, the chipset can be capable of enabling a computing device tooperate in the system 300 when implemented on or otherwise operablycoupled to the computing device. Thus, for example, one or morecomponents of the apparatus 400 can provide a chipset configured toenable a computing device to operate over a wireless network. In somesuch example embodiments, one or more components of the apparatus 400can be embodied on a cellular chipset.

In some example embodiments, the processing circuitry 410 can include aprocessor 412 and, in some embodiments, such as that illustrated in FIG.4, can further include memory 414. The processing circuitry 410 can bein communication with or otherwise control a transceiver 416, userinterface 418, and/or scanning control module 420.

The processor 412 can be embodied in a variety of forms. For example,the processor 412 can be embodied as various hardware-based processingmeans such as a microprocessor, a coprocessor, a controller or variousother computing or processing devices including integrated circuits suchas, for example, an ASIC (application specific integrated circuit), anFPGA (field programmable gate array), some combination thereof, or thelike. Although illustrated as a single processor, it will be appreciatedthat the processor 412 can comprise a plurality of processors. Theplurality of processors can be in operative communication with eachother and can be collectively configured to perform one or morefunctionalities of the apparatus 400 as described herein. In someexample embodiments, the processor 412 can be configured to executeinstructions that can be stored in the memory 414 or that can beotherwise accessible to the processor 412. As such, whether configuredby hardware or by a combination of hardware and software, the processor412 capable of performing operations according to various embodimentswhile configured accordingly.

In some example embodiments, the memory 414 can include one or morememory devices. Memory 414 can include fixed and/or removable memorydevices. In some embodiments, the memory 414 can provide anon-transitory computer-readable storage medium that can store computerprogram instructions that can be executed by the processor 412. In thisregard, the memory 414 can be configured to store information, data,applications, instructions and/or the like for enabling the apparatus400 to carry out various functions in accordance with one or moreexample embodiments. In some embodiments, the memory 414 can be incommunication with one or more of the processor 412, transceiver 416,user interface 418, or scanning control module 420 via one or more busesfor passing information among components of the apparatus 400.

The apparatus 400 can further include one or more transceivers,collectively illustrated and referenced as transceiver 416. Thetransceiver 416 can enable the apparatus 400 to send wireless signals toand receive signals from one or more wireless networks. In this regard,the transceiver 416 can be configured to support sending wirelesssignals to and receiving wireless signals from a network access point304. As such, the transceiver 416 can be configured to supportcommunication via any type of cellular or other wireless communicationtechnology that can be supported by the wireless communication device302 and/or network access point 304.

In some example embodiments, the apparatus 400 can include the userinterface 418. It will be appreciated, however, that in some exampleembodiments, one or more aspects of the user interface 418 can beomitted, and in some embodiments, the user interface 418 can be omittedentirely. The user interface 418 can be in communication with theprocessing circuitry 410 to receive an indication of a user input and/orto provide an audible, visual, mechanical, or other output to a user. Assuch, the user interface 418 can include, for example, a keyboard, amouse, a joystick, a display, a touch screen display, a microphone, aspeaker, one or more biometric input devices, and/or other input/outputmechanisms. In embodiments wherein the user interface 418 comprises atouch screen display, the user interface 418 can additionally beconfigured to detect and/or receive an indication of a touch gesture orother input to the touch screen display.

The apparatus 400 can further include scanning control module 420. Thescanning control module 420 can be embodied as various means, such ascircuitry, hardware, a computer program product comprising a computerreadable medium (for example, the memory 414) storing computer readableprogram instructions executable by a processing device (for example, theprocessor 412), or some combination thereof. In some embodiments, theprocessor 412 (or the processing circuitry 410) can include, orotherwise control the scanning control module 420. As described furtherherein below, the scanning control module 420 can be configured tocontrol the performance of adaptive OOS scanning in accordance withvarious example embodiments.

The scanning control module 420 of some example embodiments can beconfigured to implement a statistical mode for adaptively selecting ascan mode to use in the event of an OOS condition. More particularly,the scanning control module 420 of some example embodiments can beconfigured to leverage the statistical behavior for a received signalquality measurement quality from a serving network access point (e.g., aserving network access point 104) before the OOS condition. In thisregard, the scanning control module 420 can be configured to estimatethe cause of the OOS condition based at least in part on one or morereceived signal quality measurements before the wireless communicationdevice 302 experienced the OOS condition and completed the initial scanwithout reacquiring network service. The signal quality measurement(s)that can be used by the scanning control module 420 to make thisestimation can be any appropriate measurement of a received signal powerand/or other signal quality indication in accordance with a RAT used bythe network to which the wireless communication device 302 was connectedprior to the OOS condition. By way of non-limiting example, the scanningcontrol module 420 can use a reference signal received power (RSRP)measurement, reference signal received quality (RSRQ) measurement,received signal code power (RSCP) measurement, received signal strengthindicator (RSSI) measurement, some combination thereof, and/or the liketo measure the received signal quality.

In some example embodiments implementing a statistical mode, thescanning control module 420 can be configured to use one or morereceived signal quality measurements captured prior to the OOS conditionto determine a rate of degradation of the received signal quality priorto the OOS condition. In cases of gradual decrease for mean signalquality values (e.g., RSRP, RSRQ, RSCP, RSSI and/or other values), it islikely that the wireless communication device 302 is either in acoverage hole or a remote area with no cellular coverage (e.g., a remotemountain or island with no cellular deployment) in which reacquiringnetwork coverage may not be possible without a relatively substantiallocation change for the wireless communication device 302. In cases ofsudden pathloss increase that results in an OOS condition, the wirelesscommunication device 302 may be in a temporary deep shadowing scenario(e.g., an elevator in an urban setting that generally has propercellular coverage) where reacquisition of network service could happenwith a relatively minimal location change by the wireless communicationdevice 302. FIG. 5 illustrates an example of received power vs. distancedata for large scale pathloss in an urban scenario and an example ofreceived power vs. time data in a small scale fading scenario, whichillustrate how signal quality degradation models can be applied toestimate a cause (e.g., temporary deep shadowing versus entering acoverage hole) of an OOS condition in accordance with some exampleembodiments.

The scanning control module 420 can be configured to set a displacementthreshold, d_(threshold), which can, for example, be defined in terms ofa scalar distance traveled threshold, based at least in part on theestimated nature (e.g., cause) of the OOS condition. The displacementthreshold can represent a minimum threshold distance (e.g., an estimateddistance) that the wireless communication device 302 needs to travelduring the OOS condition before it is estimated that the wirelesscommunication device 302 is likely to be within network coverage. Thedisplacement threshold can be set to a higher magnitude (e.g., value) inscenarios where the mean pathloss gradually increases (e.g., inscenarios in which it is estimated that the OOS condition resulted fromthe wireless communication device 302 entering a coverage gap) comparedto the scenarios where wireless communication device 302 lost coveragedue to a sudden increase in pathloss (e.g., in scenarios in which it isestimated that the OOS condition resulted from a deep shadowingscenario). Thus, for example, if the rate of degradation of one or morereceived signal quality metrics prior to the OOS condition exceeds athreshold rate of degradation (e.g., a rate of degradation indicative ofa deep shadowing condition), the scanning control module 420 can set afirst displacement threshold, while if the rate of degradation of one ormore received signal quality metrics prior to the OOS condition does notexceed the threshold rate of degradation, the scanning control module420 can set a second displacement threshold. The first displacementthreshold can have a smaller magnitude than the second displacementthreshold, as the wireless communication device 302 may not have totravel as far to reacquire network service when experiencing a deepshadowing condition than when in a coverage hole.

The scanning control module 420 of some example embodiments can beconfigured to implement a deterministic mode for adaptively selecting ascan mode to use in the event of an OOS condition. Embodimentsimplementing a deterministic mode can leverage pre-harvestedlocation-coverage mapping information mapping location data tocorresponding indications of whether cellular network and/or othernetwork coverage is available in respective locations. In this regard,the location-coverage mapping information can include mappinginformation indicative of an extent of network coverage within an areain which the wireless communication device is located when the OOScondition occurs. For example, the location-coverage mapping informationcan include a binary indication of whether coverage is available orunavailable at a given location. As another example, thelocation-coverage mapping information can include an indication of anetwork signal quality, such as in terms of RSRP, RSRQ, RSCP, RSSI,and/or the like, at a given location.

The location-coverage mapping information can, for example, be collectedby the coverage information provisioning apparatus 306 from wirelesscommunication devices, such as wireless communication device 302,operating within the system 300. In this regard, the coverageinformation provisioning apparatus 306 can be configured to harvestposition data and corresponding network coverage information for devicesoperating within the system 300. The position data can, for example, becoordinate data, such as can be determined by the device and/or by thecoverage information provisioning apparatus 306 for a correspondingnetwork service measurement through usage of a satellite navigationsystem, such as Global Positioning System (GPS), GLONASS (GlobalNavigation Satellite System), Compass system, Galileo system, or othersatellite navigation system. The coverage information provisioningapparatus 306 can be configured to store the harvested mappinginformation and identify regions according to the average observedcellular coverage (e.g., according to whether coverage is indicated asbeing available/unavailable on average in a location; and/or accordingto the average signal quality measurement in a location) for respectivelocations.

The location-coverage mapping information of some example embodimentscan include mapping information collected over a number of users invarious locations for multiple RATs. Thus, for example, the coverageinformation provisioning apparatus 306 of some example embodiments canbe configured to maintain one set of location-coverage mappinginformation for LTE coverage, and another set of location-coveragemapping information for UMTS coverage.

The coverage information provisioning apparatus 306 can be configured toprovision location-coverage mapping information to the wirelesscommunication device 302. An example of the provisioning oflocation-coverage mapping information to the wireless communicationdevice 302 in accordance with some example embodiments is illustrated inFIG. 6. With reference to FIG. 6, operation 602 can include the coverageinformation provisioning apparatus 306 collecting location data andcorresponding cellular coverage metrics for one or more RATs from userdevices. The location data can, for example, be satellite positioningsystem-based location data, such as GPS-based location data. Thecellular coverage metrics can, for example, include observed receivedsignal quality metrics, such as RSRP, RSRQ, RSCP, RSSI, and/or the like.As another example, the cellular coverage metrics can additionally oralternatively include indications of whether network coverage isavailable/unavailable in respective locations.

Operation 604 can include the coverage information provisioningapparatus 306 forming and updating the location-cellular coveragemapping information based on data collected in operation 602. Thecollection of location data and corresponding coverage metrics andupdating the location-coverage mapping information based on newlycollected location data coverage metrics can be an ongoing process.Operation 606 can include the coverage information provisioningapparatus 306 identifying out of coverage regions, cellular coverageholes, and areas with lack of network deployment.

In some example embodiments the coverage information provisioningapparatus 306 can be configured to proactively push location-coveragemapping information to the wireless communication device 302.Additionally or alternatively, in some example embodiments, such as theexample illustrated in operation 608 of FIG. 6, the wirelesscommunication device 302 can query the coverage information provisioningapparatus 306 to download location-coverage mapping information. Thequery can, for example, include an indication of a current location ofthe wireless communication device 302 such that the wirelesscommunication device 302 can download location-coverage mappinginformation for a region proximate to the location of the wirelesscommunication device 302. In this regard, the wireless communicationdevice 302 of some example embodiments can download location-coveragemapping information for one or more areas proximate to the wirelesscommunication device 302 at a given time rather than downloading globallocation-coverage mapping information.

In some example embodiments, the query of operation 608 can furtherspecify a proximity or range relative to the current location of thewireless communication device 302 such that the wireless communicationdevice 302 can define a range or area of location-coverage mappinginformation relative to the device's location to download.

In some embodiments, the query can additionally or alternatively includean indication of a direction of travel of the wireless communicationdevice 302 and/or a velocity of the wireless communication device 302,which can be used by the coverage information provisioning apparatus 306to select the location-coverage mapping information to provide to thewireless communication device 302 in response to the query. For example,location-coverage mapping information covering a defined distance oftravel in the direction in which the wireless communication device 302is moving (e.g., location-coverage mapping information for the next nmiles in the direction of travel) can be provisioned to the wirelesscommunication device 302. As another example, location-coverage mappinginformation covering an area which the wireless communication device 302would traverse over a defined length of time given its direction oftravel and/or velocity (e.g., location-coverage mapping information forthe next n minutes of travel) can be provisioned to the wirelesscommunication device 302.

As a non-limiting example, the query can be defined as: Query function(Current Location, Proximity to Current Location, direction, velocity).“Current Location” can be a parameter specifying the location of thewireless communication device 302 at the time of the query. “Proximityto Current Location” can be a parameter specifying a range or area oflocation-coverage mapping information relative to the device's CurrentLocation to download. “Direction” can be a parameter indicating adirection of travel of the wireless communication device 302 at the timeof the query. “Velocity” can be a parameter specifying a velocity of thewireless communication device 302 at the time of the query. It will beappreciated, however, that one or more of the parameters in the exampleQuery function can be omitted in accordance with some exampleembodiments. Further, the Query function of some example embodiments caninclude one or more parameters in addition to or in lieu of one or moreof the parameters described in the example above. As a more particularexample, if the wireless communication device 302 queries forlocation-coverage mapping information within 10 kilometers (km) oflocation [x,y,z], the Query can be specified as: Query function (x,y,z;10 km proximity to x,y,z position).

In some example embodiments, the query of operation 608 can be periodic.For example, the wireless communication device 302 of some exampleembodiments can be configured to query for location-coverage mappinginformation every half hour, every hour, and/or some other periodic unitof time. As another example, the wireless communication device 302 ofsome example embodiments can be configured to query forlocation-coverage mapping information in response to traveling apredefined distance, such as every 10 miles of travel. In some exampleembodiments, the query of operation 708 can be event based. For example,the wireless communication device 302 of some example embodiments can beconfigured to query for location-coverage mapping information inresponse to the device moving out of range and/or within a predefineddistance (e.g., 1 mile) of being out of range of previously receivedlocation-coverage mapping information.

The coverage information provisioning apparatus 306 can be configured toreceive the query of operation 608 and can be configured to respond byprovisioning the requested location-coverage mapping information to thewireless communication device 302 in response to the query, asillustrated by operation 610. The granularity of the provisioned mappinginformation can be determined by the coverage information provisioningapparatus based at least in part on the location of the wirelesscommunication device 302. For example, mapping information withincreased (e.g., greater) granularity can be provided in an instance inwhich the wireless communication device 302 is located in an urbansetting, while mapping information with a decreased (e.g., lesser)granularity can be provided in an instance in which the wirelesscommunication device 302 is located in a suburban or rural setting.

The provisioned mapping information can have any of a variety offormats. For example, in some embodiments, the provisioned mappinginformation can be Boolean data. In such example embodiments, a Booleanvalue can be mapped to each of one or more respective locations forwhich mapping information is provisioned. For example, a Boolean valueof “1” can indicate that service is available in the location, while aBoolean value of “0” can indicate that no service is available in thelocation (e.g., “out of service”). It will be appreciated, however, thatthese Boolean values can be reversed in some embodiments such that “0”can indicate that service is available, while “1” can indicate that thelocation is an out of service location. Embodiments utilizing Booleanvalues for mapping data can provide a small payload size for themessage(s) used to provision mapping information, as in some suchexample embodiments, only a single Boolean value, or one Boolean valuefor each RAT for which location-coverage mapping information isprovisioned, may be mapped to each respective location.

Additionally or alternatively, the provisioned mapping information ofsome example embodiments can include more detailed location-coveragemapping information than Boolean data. For example, the mappinginformation of some example embodiments can include a measured receivedsignal quality value (e.g., average measured signal quality value) foreach of one or more locations for which mapping information isprovisioned. The received signal quality values can, for example,include RSRP, RSRQ, RSCP, RSSI, and/or the other signal quality valuesthat can be mapped to respective locations for which mapping informationis provisioned.

In some example embodiments, mapping information can be provisioned formultiple RATS. For example, in some example embodiments in which mappinginformation includes measured signal quality values, mapping informationcan be specified for various cellular RATs, such as LTE, UMTS, and GSM,as follows:

Satellite Navigation System (e.g., GPS) Position Data Average CellularCoverage Metrics (longitude, latitude, elevation) - RAT Type: [CellularPower for Channel [x, y, z] Estimation, Received Signal Quality] [x₁,y₁, z₁] LTE: [RSRP₁, RSRQ₁] UMTS: [RSCP₁, RSSI₁] [x₂, y₂, z₂] UMTS:[RSCP₂, RSSI₂] GSM: [RSSI₂] [x₃, y₃, z₃] GSM: [RSSI₃]

The scanning control module 420 can be configured to uselocation-coverage mapping information provisioned to the wirelesscommunication device 302 to determine whether an OOS condition is due todeployment limitations, or due to a deep shadowing condition. Thescanning control module 420 can be further configured to define adisplacement threshold based at least in part on the determined cause ofthe OOS condition. For example, if the location-coverage mappinginformation indicates that the wireless communication device 302 is in alocation known to have weak coverage or no coverage, the scanningcontrol module 420 can determine that the cause of the OOS condition isdue to deployment limitations. However, if the location-coverage mappinginformation indicates that the wireless communication device 302 is inan area known to have good coverage, the scanning control module 420 canbe configured to determine that the cause of the OOS condition is due toa deep shadowing condition. In the case that the scanning control module420 determines that the cause of the OOS condition is deploymentlimitations, the scanning control module 420 can select to use a lessaggressive scan mode and/or to set a larger displacement threshold thanin the case that the scanning control module 420 determines that thecause of the OOS condition is a deep shadowing condition.

The scanning control module 420 can be configured to use thepre-downloaded location-coverage mapping information to define adisplacement threshold according to a closest location(s) known to havenetwork coverage compared to the location at which the OOS conditionoccurred. Thus, for example, if a location a half mile from the locationof the wireless communication device 302 when the OOS condition occurredis known from the location-coverage mapping information to havecoverage, the magnitude of the displacement threshold can be set to ahalf mile.

In some example embodiments implementing a deterministic mode, thescanning control module 420 can be configured to define a displacementthreshold in terms of a threshold displacement vector, Δthreshold,according to a closest coverage region(s) compared to the location whereOOS condition occurred. In embodiments in which the displacementthreshold is defined as a displacement vector, the displacement vectorcan define a threshold displacement magnitude and an associateddisplacement direction (e.g., a direction of travel), which can, forexample, correspond to a direction of travel of the wirelesscommunication device 302 during the OOS condition. Thus, for example, ifthe wireless communication device 302 is traveling at a bearing of 270°and the closest location known to have network coverage at that bearingis one mile from the location of the wireless communication device 302at the time the OOS condition occurred, a threshold displacement vectorhaving a magnitude of one mile and direction of 270° can be defined. Insome example embodiments, multiple threshold displacement vectors can bedefined, with each threshold displacement vector having a differentassociated displacement direction and corresponding displacementmagnitude determined based at least in part on the location-coveragemapping information such that different thresholds can be appliedrelative to the location at which the OOS condition occurred inscenarios in which the displacement direction of the wirelesscommunication device 302 varies during the OOS condition.

The scanning control module 420 can be further configured to determine adisplacement magnitude indicative of a distance traveled by the wirelesscommunication device 302 during the OOS condition. In this regard, thedisplacement magnitude can be a distance of displacement of the wirelesscommunication device 302 from the location at which the OOS conditionoccurred. The scanning control module 420 can be configured to comparethe displacement magnitude to the displacement threshold set in responseto the OOS condition (e.g., via statistical and/or deterministic modetechniques as described above) to determine if the displacementthreshold has been satisfied. If the displacement magnitude exceeds thedisplacement threshold, the scanning control module 420 can beconfigured to determine that the displacement threshold has beensatisfied. In embodiments in which the displacement threshold is definedin terms of a threshold displacement vector, such as when usingdeterministic mode to set a threshold displacement vector based onpre-downloaded location-coverage mapping information, the scanningcontrol module 420 can be configured to determine if the displacementmagnitude in the displacement direction (e.g., direction of travel) ofthe wireless communication device 302 satisfies the magnitude of athreshold displacement vector corresponding to the displacementdirection of the wireless communication device 302.

In an instance in which the displacement threshold has been satisfied,the scanning control module 420 can be configured to use a moreaggressive scan mode than if the displacement threshold has not beensatisfied. In this regard, if the displacement threshold has beensatisfied, it can be assumed that it is likely that network service canbe reacquired. Thus, for example, if the displacement threshold has beensatisfied, the scanning control module 420 can be configured to triggeran instantaneous scan and the scan frequency can be increased at leasttemporarily to provide for faster reacquisition of network service. If,however, the displacement threshold has not been satisfied, the scanningcontrol module 420 can use a less aggressive scan mode to avoid excessbattery consumption from performance of frequent scans in situations inwhich it is unlikely that network service can be reacquired.

The scanning control module 420 can be configured to use any of avariety of techniques to determine a displacement magnitude and/ordisplacement direction for the wireless communication device 302 duringthe OOS condition. For example, in embodiments in which the wirelesscommunication device 302 includes a satellite navigation system sensor,such as a GPS sensor, the scanning control module 420 can be configuredto use position information that can be determined via GPS and/or othersatellite navigation system to determine a distance traveled by thewireless communication device 302 during the OOS condition and/or adisplacement direction of the wireless communication device 302. Asanother example, in embodiments in which the wireless communicationdevice 302 includes an accelerometer, the scanning control module 420can be configured to use accelerometer measurements to approximate adisplacement magnitude and/or displacement direction for the wirelesscommunication device 302 during the OOS condition.

In some example embodiments in which the wireless communication device302 includes a satellite navigation system sensor and an accelerometer,usage of the satellite navigation system sensor can be preferred to theaccelerometer for determination of displacement magnitude and/ordisplacement magnitude. Thus, for example, the satellite navigationsystem sensor can be used to determine a displacement magnitude and/ordisplacement direction for the wireless communication device 302 ifsatellite navigation system service is available during the OOScondition. However, if satellite navigation system service is also outof service during the OOS condition, the accelerometer can be used toapproximate the displacement magnitude and/or displacement direction ofthe wireless communication device 302. It will be appreciated, however,that some example embodiments can use accelerometer and/or otheravailable location and/or sensor data to supplement position data thatcan be obtained through the use of a satellite navigation system.

In some example embodiments, the scanning control module 420 can beconfigured to select an adaptive scan mode to apply in an OOS conditionbased at least in part on user triggered events and conditions. In thisregard, the scanning control module 420 can be configured to determinebased at least in part on user triggered events preceding (e.g.,immediately and/or otherwise closely preceding) the OOS condition and/oruser triggered events occurring during the OOS condition whether thedevice user desires to perform an action requiring network serviceduring the OOS condition. In such example embodiments, the scanningcontrol module 420 can be configured to monitor for user input to theuser interface 418 that can be indicative of a user desire to perform anaction requiring network service during the OOS condition. For example,the scanning control module 420 can be configured to monitor for touchscreen events; an input to a keypad; user attempt to initiate a call(e.g., a voice call and/or data call); user attempt to initiate anemergency call; a pending text message, such as a short message service(SMS) message, multimedia messaging service (MMS) message, and/or othertext message; and/or other user triggered events that can be indicativeof a user desire to perform an action requiring network service forperformance.

In an instance in which a user triggered event and/or conditionindicative of a user desire to perform an action requiring networkservice for performance is detected, the scanning control module 420 ofsome example embodiments can be configured to use a more aggressive scanmode to scan for network coverage than would otherwise be used so as tosupport faster recovery from the OOS condition. In some such exampleembodiments, the scanning control module 420 can be configured totrigger an instantaneous scan and adapt the scan frequency according todevice mobility conditions in response to a user triggered event and/orcondition indicative of a user desire to perform an action requiringnetwork service for performance. Additionally or alternatively, thescanning control module 420 of some such example embodiments can beconfigured to use a more aggressive scan mode even if a displacementthreshold, such as can be set using the statistical and/or deterministicmodes described above, has not been satisfied by mobility of thewireless communication device 302 during the OOS condition.

FIG. 7 illustrates a flowchart according to an example method foradaptive out of service scanning according to some example embodiments.In this regard, FIG. 7 illustrates operations that can be performed bythe wireless communication device 302 of some example embodiments. Oneor more of processing circuitry 410, processor 412, memory 414,transceiver 416, user interface 418, or scanning control module 420 can,for example, provide means for performing the operations illustrated inand described with respect to FIG. 7.

Operation 700 can include the wireless communication device 302detecting occurrence of an OOS condition. Operation 710 can include thewireless communication device 302 setting a displacement threshold inresponse to the OOS condition. The displacement threshold can, forexample, be set to a magnitude indicative of a minimum thresholddistance that it is estimated that the wireless communication device 302needs to travel from its location at the point of occurrence of the OOScondition before it is estimated that the wireless communication device302 is likely to be within network coverage such that network servicecan be reacquired. The displacement threshold can, for example, be setusing statistical mode and/or deterministic mode techniques inaccordance with one or more embodiments as described above.

Operation 720 can include the wireless communication device 302determining a displacement magnitude indicative of a distance traveledby the wireless communication device during the OOS condition. Operation730 can include the wireless communication device 302 comparing thedisplacement magnitude determined in operation 720 to the displacementthreshold set in operation 710 to determine whether the displacementmagnitude exceeds the displacement threshold.

In an instance in which it is determined in operation 730 that thedisplacement magnitude exceeds the displacement threshold, the methodcan proceed to operation 740, which can include the wirelesscommunication device 302 using a first scan mode (e.g., an aggressivescan mode) to scan for network coverage. If, however, it is determinedin operation 730 that the displacement magnitude exceeds thedisplacement threshold, the method can instead proceed to operation 750,which can include the wireless communication device 302 using a secondscan mode (e.g., a passive scan mode) to scan for network coverage. Thefirst scan mode can have a greater scan frequency than the second scanmode. In this regard, a more aggressive scan mode can be used in aninstance in which the displacement magnitude exceeds the displacementthreshold, as it can be assumed that it is likely that network servicecan be reacquired after the wireless communication device 302 hastraveled at least the displacement threshold distance during the OOScondition. However, a less aggressive, or passive, scan mode can be usedwhen the displacement magnitude does not exceed the displacementthreshold in order to reduce battery consumption, as it can be unlikelythat network service can be successfully reacquired if the wirelesscommunication device 302 has not traveled at least the displacementthreshold distance during the OOS condition.

In some example embodiments, if it is determined at operation 730 thatthe displacement magnitude does not exceed the displacement threshold,operations 720 and 730 can be repeated (e.g., periodically) during theOOS condition until either network service is reacquired using thesecond scan mode or until the wireless communication device 302 hastraveled a distance during the OOS condition that is sufficient tosatisfy the displacement threshold and has switched to using the first(e.g., aggressive) scan mode in response to the displacement thresholdbeing satisfied.

FIG. 8 illustrates a flowchart according to another example method foradaptive out of service scanning according to some example embodiments.In this regard, FIG. 8 illustrates operations that can be performed bythe wireless communication device 302 in accordance with performing someembodiments of the method of FIG. 7. One or more of processing circuitry410, processor 412, memory 414, transceiver 416, user interface 418, orscanning control module 420 can, for example, provide means forperforming the operations illustrated in and described with respect toFIG. 8.

As illustrated by operation 800, the method can begin with the wirelesscommunication device 302 being in an OOS condition and having completedan initial scan without successfully reacquiring network service.Operation 810 can include the wireless communication device 302 settinga displacement threshold. The displacement threshold can, for example,be set to a magnitude indicative of a minimum threshold distance that itis estimated that the wireless communication device 302 needs to travelfrom its location at the point of occurrence of the OOS condition beforeit is estimated that the wireless communication device 302 is likely tobe within network coverage such that network service can be reacquired.In this regard, operation 810 can correspond to an embodiment ofoperation 710 as described with respect to FIG. 7.

In some example embodiments, operation 810 can include setting thedisplacement threshold as a function of pre-downloaded harvested dataindicative of location-coverage mapping information in the vicinity ofthe wireless communication device 302, such as in accordance with one ormore embodiments implementing a deterministic mode, as described above.The pre-downloaded harvested data can be provisioned to the wirelesscommunication device 302 by the coverage information provisioningapparatus 306, such as by the process illustrated in and discussed withrespect to FIG. 6. In some embodiments in which the displacementthreshold is set as a function of location-coverage mapping information,the displacement threshold can be defined in terms of one or morethreshold displacement vectors, which can be represented as Δthreshold.A threshold displacement vector can define a threshold displacementmagnitude and an associated displacement direction (e.g., a direction oftravel), which can, for example, correspond to a direction of travel ofthe wireless communication device 302 during the OOS condition. In thisregard, a threshold displacement vector can define a minimum thresholddistance that it is estimated that the wireless communication device 302needs to travel in a given displacement direction from its location atthe point of occurrence of the OOS condition before it is estimatedbased on location-coverage mapping information that the wirelesscommunication device 302 is likely to be within network coverage suchthat network service can be reacquired.

In some example embodiments, operation 810 can additionally oralternatively include the wireless communication device 302 setting adisplacement threshold, d_(threshold), as a function of statisticalbehavior of a received signal prior to the OOS condition. For example,the displacement threshold can be set based at least in part on a rateof degradation of the received signal quality prior to the OOScondition, such as in accordance with one or more embodimentsimplementing a statistical mode, as described above. In some exampleembodiments, statistical behavior of the received signal prior to theOOS condition can be used to set the displacement threshold in aninstance in which pre-downloaded location-coverage mapping informationis not available for the area in which the wireless communication device302 is located.

Operation 820 can include the wireless communication device 302initiating an adaptive scanning mode based on the displacement thresholdset in operation 810. Operation 830 can include the wirelesscommunication device 302 determining the displacement of the deviceduring the OOS condition. In some example embodiments, operation 830 caninclude the wireless communication device 302 determining a displacementmagnitude, d, indicative of a distance traveled by the wirelesscommunication device during the OOS condition. In some exampleembodiments, such as some embodiments in which operation 810 includesdefining a threshold displacement vector, Δthreshold, operation 830 caninclude determining a displacement vector, Δ, defined by a displacementmagnitude, d, indicative of a distance traveled by the wirelesscommunication device during the OOS condition and an associateddisplacement direction indicative of a direction of travel of thewireless communication device 302 during the OOS condition.

Operation 840 can include the wireless communication device 302determining whether the displacement magnitude/vector determined inoperation 830 exceeds the displacement threshold set in operation 810.In this regard, operation 840 can correspond to an embodiment ofoperation 730.

In an instance in which it is determined in operation 840 that thedisplacement magnitude/vector determined in operation 830 does exceedthe displacement threshold set in operation 810, the method can proceedto operation 850, which can include the wireless communication device302 using an aggressive scan mode to scan for network coverage.Operation 850 can, for example, correspond to an embodiment of operation740. In some example embodiments, using the aggressive scan mode caninclude the wireless communication device 302 triggering aninstantaneous search. If the initial search is unsuccessful, theaggressive scan mode can include gradually decreasing scanning intervalsfor subsequent scans via a backoff mechanism. However, the scanningfrequency can be greater than a scan frequency that can be used in apassive scan mode in operation 860 in an instance in which thedisplacement magnitude/vector determined in operation 830 does notexceed the displacement threshold set in operation 810. Operation 850can also include setting a scanning timer, T_active_scan timer, when theaggressive scan mode is triggered. T_active_scan timer can, for example,be a countdown timer that can have an initial value that can vary withimplementation. However, if the value of T_active_scan timer reaches 0without the wireless communication device 302 successfully reacquiringnetwork service, the wireless communication device 302 can transition tothe passive scan mode of operation 860, as illustrated by operation 870.

If, on the other hand, it is determined at operation 840 that thedisplacement magnitude/vector determined in operation 830 does notexceed the displacement threshold set in operation 810, operation 850can be omitted and the method can instead proceed to operation 860,which can include the wireless communication device 302 using a passivescan mode to scan for network coverage. Operation 860 can, for example,correspond to an embodiment of operation 750. The passive scan mode canhave a lower scan frequency than the aggressive scan mode. In someexample embodiments, operation 860 can include decreasing and/orotherwise adjusting scanning intervals in the passive scan modeaccording to the device receiver velocity.

In some example embodiments, operation 860 can include the wirelesscommunication device 302 continuing to perform operations 830 and 840(e.g., periodically) during the OOS condition until either networkservice is reacquired using the passive scan mode or until the wirelesscommunication device 302 has traveled a distance during the OOScondition that is sufficient for the displacement magnitude/vector ofthe device during the OOS condition to satisfy the displacementthreshold. In the case that the displacement magnitude/vector of thedevice is determined at some point during the performance of operation860 to exceed the displacement threshold and network service has not yetbeen reacquired, the wireless communication device 302 can transitionfrom the passive scan mode to the aggressive scan mode of operation 850.

FIG. 9 illustrates a flowchart according to an example method foradaptive out of service scanning based on a rate of degradation in areceived signal quality prior to an out of service condition accordingto some example embodiments. In this regard, FIG. 9 illustratesoperations that can be performed by the wireless communication device302 in accordance with performing some embodiments of the method of FIG.7 in which statistical characteristics of a received signal prior to theOOS condition can be used to set the displacement threshold, such as inaccordance with one or more embodiments implementing a statistical modeas described above. One or more of processing circuitry 410, processor412, memory 414, transceiver 416, user interface 418, or scanningcontrol module 420 can, for example, provide means for performing theoperations illustrated in and described with respect to FIG. 9.

Operation 900 can include the wireless communication device 302detecting occurrence of an OOS condition. In this regard, operation 900can correspond to an embodiment of operation 700.

Operation 910 can include the wireless communication device 302determining a rate of degradation of a received signal quality prior tothe OOS condition. The rate of degradation can, for example, bedetermined through or more received signal quality measurements capturedprior to the OOS condition. The received signal quality measurements caninclude RSRP, RSRQ, RSCP, RSSI, and/or other signal quality measurementsdepending on a type of RAT which was used by the wireless communicationdevice 302 prior to the OOS condition. Operation 920 can include thewireless communication device 202 setting a displacement threshold(e.g., d_(threshold)) based at least in part on the rate of degradationof the received signal quality prior to the OOS condition. In thisregard, operation 920 can be an embodiment of operation 710.

As an example, if the rate of degradation of the received signal qualityprior to the OOS condition exceeds a threshold rate of degradation, thewireless communication device 302 can estimate that the cause of the OOScondition is a deep shadowing condition, and can set a firstdisplacement threshold at operation 920. If, however, the rate ofdegradation of the received signal quality does not exceed the thresholdrate of degradation, the wireless communication device 302 can estimatethat the cause of the OOS condition is that the wireless communicationdevice 302 is in a coverage hole, and can set a second displacementthreshold at operation 920. The first displacement threshold can have asmaller magnitude than the second displacement threshold, as it can beestimated that network service can be reacquired after a smallerdistance of travel in a deep shadowing scenario than in a scenario inwhich the wireless communication device 302 is in a coverage hole.

Operation 930 can include the wireless communication device 302determining a displacement magnitude indicative of a distance traveledby the wireless communication device 302 during the OOS condition. Inthis regard, operation 930 can correspond to an embodiment of operation720. Operation 940 can include the wireless communication device 302comparing the displacement magnitude determined in operation 930 to thedisplacement threshold set in operation 920 to determine whether thedisplacement magnitude exceeds the displacement threshold. In thisregard, operation 940 can correspond to an embodiment of operation 730.

In an instance in which it is determined in operation 940 that thedisplacement magnitude exceeds the displacement threshold, the methodcan proceed to operation 950, which can include the wirelesscommunication device 302 using a first scan mode (e.g., an aggressivescan mode) to scan for network coverage. In this regard, operation 950can correspond to an embodiment of operation 740. If, however, it isdetermined in operation 940 that the displacement magnitude exceeds thedisplacement threshold, the method can instead proceed to operation 960,which can include the wireless communication device 302 using a secondscan mode (e.g., a passive scan mode) to scan for network coverage. Inthis regard, operation 960 can correspond to an embodiment of operation750. The first scan mode can have a greater scan frequency than thesecond scan mode. In this regard, a more aggressive scan mode can beused in an instance in which the displacement magnitude exceeds thedisplacement threshold, as it can be assumed that it is likely thatnetwork service can be reacquired after the wireless communicationdevice 302 has traveled at least the displacement threshold distanceduring the OOS condition. However, a less aggressive, or passive, scanmode can be used when the displacement magnitude does not exceed thedisplacement threshold in order to reduce battery consumption, as it canbe unlikely that network service can be successfully reacquired if thewireless communication device 302 has not traveled at least thedisplacement threshold distance during the OOS condition.

In some example embodiments, if it is determined at operation 940 thatthe displacement magnitude does not exceed the displacement threshold,operations 930 and 940 can be repeated (e.g., periodically) during theOOS condition until either network service is reacquired using thesecond scan mode or until the wireless communication device 302 hastraveled a distance during the OOS condition that is sufficient tosatisfy the displacement threshold and has switched to using the first(e.g., aggressive) scan mode in response to the displacement thresholdbeing satisfied.

FIG. 10 illustrates a flowchart according to an example method foradaptive out of service scanning based on location-coverage mappinginformation according to some example embodiments. In this regard, FIG.10 illustrates operations that can be performed by the wirelesscommunication device 302 in accordance with performing some embodimentsof the method of FIG. 7 in which pre-downloaded location-coveragemapping information can be used to set the displacement threshold, suchas in accordance with one or more embodiments implementing adeterministic mode as described above. One or more of processingcircuitry 410, processor 412, memory 414, transceiver 416, userinterface 418, or scanning control module 420 can, for example, providemeans for performing the operations illustrated in and described withrespect to FIG. 10.

Operation 1000 can include the wireless communication device 302receiving location-coverage mapping information. The location-coveragemapping information can be provisioned to the wireless communicationdevice 302 by the coverage information provisioning apparatus 306, suchas by the process illustrated in and described with respect to FIG. 6.

Operation 1010 can include the wireless communication device 302detecting occurrence of an OOS condition. In this regard, operation 1010can correspond to an embodiment of operation 700.

Operation 1020 can include the wireless communication device 302 settinga displacement threshold based at least in part on the location-coveragemapping information received in operation 1000 in response to the OOScondition. In this regard, operation 1020 can, for example, include thewireless communication device 302 using the location-coverage mappinginformation to determine a distance which the wireless communicationdevice 302 has to travel from the position of occurrence of the OOScondition before the wireless communication device 302 is in a locationindicated as having network coverage by the location-coverage mappinginformation. In some example embodiments, operation 1020 can includedefining the displacement threshold as a threshold displacement vector,Δthreshold. The threshold displacement vector can define a thresholddisplacement magnitude and an associated displacement direction (e.g., adirection of travel), which can, for example, correspond to a directionof travel of the wireless communication device 302 during the OOScondition. In this regard, a threshold displacement vector can define aminimum threshold distance that it is estimated that the wirelesscommunication device 302 needs to travel in a given displacementdirection from its location at the point of occurrence of the OOScondition before it is estimated based on location-coverage mappinginformation that the wireless communication device 302 is likely to bewithin network coverage such that network service can be reacquired.Operation 1020 can accordingly correspond to an embodiment of operation710.

Operation 1030 can include the wireless communication device 302determining a displacement magnitude indicative of a distance traveledby the wireless communication device 302 during the OOS condition. Insome example embodiments, such as some embodiments in which thedisplacement threshold set in operation 1020 is defined as a thresholddisplacement vector, operation 1020 can include determining adisplacement vector, Δ, defined by a displacement magnitude, d,indicative of a distance traveled by the wireless communication deviceduring the OOS condition and an associated displacement directionindicative of a direction of travel of the wireless communication device302 during the OOS condition. Operation 1030 can correspond to anembodiment of operation 720.

Operation 1040 can include the wireless communication device 302comparing the displacement magnitude determined in operation 1030 to thedisplacement threshold set in operation 1020 to determine whether thedisplacement magnitude exceeds the displacement threshold. Inembodiments in which the displacement threshold is defined as athreshold displacement vector and a displacement vector is determined inoperation 1030, operation 1040 can include comparing the displacementvector determined in operation 1030 to a threshold displacement vectorhaving a corresponding displacement direction to the displacement vectordetermined in operation 1030. In this regard, given varying directionsof travel of the wireless communication device, different thresholddisplacement magnitudes can be defined for different directions oftravel. Operation 104 can correspond to an embodiment of operation 730.

In an instance in which it is determined in operation 1040 that thedisplacement magnitude exceeds the displacement threshold, the methodcan proceed to operation 1050, which can include the wirelesscommunication device 302 using a first scan mode (e.g., an aggressivescan mode) to scan for network coverage. In this regard, operation 1050can correspond to an embodiment of operation 740. If, however, it isdetermined in operation 1040 that the displacement magnitude exceeds thedisplacement threshold, the method can instead proceed to operation1060, which can include the wireless communication device 302 using asecond scan mode (e.g., a passive scan mode) to scan for networkcoverage. In this regard, operation 1060 can correspond to an embodimentof operation 750. The first scan mode can have a greater scan frequencythan the second scan mode. In this regard, a more aggressive scan modecan be used in an instance in which the displacement magnitude exceedsthe displacement threshold, as it can be assumed that it is likely thatnetwork service can be reacquired after the wireless communicationdevice 302 has traveled at least the displacement threshold distanceduring the OOS condition. However, a less aggressive, or passive, scanmode can be used when the displacement magnitude does not exceed thedisplacement threshold in order to reduce battery consumption, as it canbe unlikely that network service can be successfully reacquired if thewireless communication device 302 has not traveled at least thedisplacement threshold distance during the OOS condition.

In some example embodiments, if it is determined at operation 1040 thatthe displacement magnitude does not exceed the displacement threshold,operations 1030 and 1040 can be repeated (e.g., periodically) during theOOS condition until either network service is reacquired using thesecond scan mode or until the wireless communication device 302 hastraveled a distance during the OOS condition that is sufficient tosatisfy the displacement threshold and has switched to using the first(e.g., aggressive) scan mode in response to the displacement thresholdbeing satisfied.

Some example embodiments implement both statistical and deterministicmodes for setting a displacement threshold in response to an OOScondition. In some such example embodiments, a deterministic mode methodcan be used to set the displacement threshold if location-coveragemapping information for the area in which the wireless communicationdevice 302 is located has been downloaded by the wireless communicationdevice 302 prior to the OOS condition. However, if location-coveragemapping information is unavailable for the area in which the wirelesscommunication device 302 is located, a statistical mode approach basedon degradation of received signal quality prior to the OOS condition canbe used to set the displacement threshold.

FIG. 11 illustrates a state diagram for selecting between application ofa deterministic mode and a statistical mode for selecting an out ofservice scan mode according to some example embodiments integrating bothstatistical and deterministic modes for setting a displacement thresholdin response to an OOS condition. At state 1100, the wirelesscommunication device 302 can be experiencing an OOS condition and canhave completed an initial scan without successfully reacquiring networkservice.

If, pre-downloaded harvested location-coverage mapping information isavailable for the area in which the wireless communication device 302 islocated, the device can transition from state 1100 to state 1110 and canapply a deterministic mode method for setting a displacement thresholdand selecting a scan mode. In some example embodiments, state 1110 caninclude the wireless communication device 302 setting a displacementthreshold defined as a threshold displacement vector, Δthreshold, as afunction of the pre-downloaded harvested data. The wirelesscommunication device 302 can make a scan mode decision(s) based ondevice mobility during the OOS condition in accordance with thepre-downloaded location-coverage mapping information. In this regard,for example, if a displacement vector, Δ, defining a displacementmagnitude and direction of travel of the wireless communication device302 exceeds a Δthreshold set for a corresponding direction of travelbased on the pre-downloaded harvested data, the wireless communicationdevice 302 can use an aggressive scan mode to scan for network coverage.If, however, mobility of the wireless communication device 302 duringthe OOS condition has not satisfied Δthreshold, the wirelesscommunication device can apply a less aggressive, or passive, scan modeto conserve battery power.

If, however, pre-downloaded harvested location-coverage mappinginformation is not available for the area in which the wirelesscommunication device 302 is located, the device can transition fromstate 1100 to state 1120 and can apply a statistical mode method forsetting a displacement threshold and selecting a scan mode. In someexample embodiments, state 1120 can include the wireless communicationdevice 302 setting a displacement threshold, d_(threshold), as afunction of statistical behavior of the received signal before the OOScondition. The wireless communication device 302 can make a scan modedecision(s) based on device mobility during the OOS condition inaccordance with the defined displacement threshold. In this regard, forexample, if the wireless communication 302 travels a distance during theOOS condition exceeding d_(threshold), the wireless communication device302 can use an aggressive scan mode to scan for network coverage, as itcan be estimated that it is likely that the wireless communicationdevice 302 is located in an area having network coverage and cansuccessfully reacquire network service. If, however, mobility of thewireless communication device 302 during the OOS condition has notsatisfied d_(threshold), the wireless communication device can apply aless aggressive, or passive, scan mode to conserve battery power.

In some example embodiments, the wireless communication device 302 canhave knowledge about the proximity of cellular coverage locations to theposition of the wireless communication device 302 from thepre-downloaded harvested location-coverage mapping information whenoperating in state 1110. This proximity can be defined as d_(Proximity).In the event that d_(Proximity) is 0, the wireless communication device302 of some example embodiments can transition from state 1110 to state1120 and can apply the statistical mode method for setting adisplacement threshold and selecting a scan mode.

FIGS. 12A and 12B illustrate a flowchart according to an example methodfor adaptive out of service scanning according to some exampleembodiments. In this regard, FIGS. 12A and 12B illustrate operationsthat can be performed by the wireless communication device 302 inaccordance with some example integrating both statistical anddeterministic mode methods. One or more of processing circuitry 410,processor 412, memory 414, transceiver 416, user interface 418, orscanning control module 420 can, for example, provide means forperforming the operations illustrated in and described with respect toFIGS. 12A and 12B.

Referring first to FIG. 12A, operation 1200 can include the wirelesscommunication device 302 determining whether it is operating in an OOScondition. If the wireless communication device 302 is not operating inan OOS condition, then the method can terminate. If, however, thewireless communication device 302 is operating in an OOS condition, themethod can proceed to operation 1205, which can include the wirelesscommunication device 302 determining if there location-coverage mappinginformation is available for the area in which the wirelesscommunication device 302 is located.

If it is determined in operation 1205 that location-coverage mappinginformation is available, the method can proceed to operation 1210,which can include the wireless communication device 302 selecting to usea deterministic mode and setting one or more threshold displacementvectors, Δthreshold. In this regard, operation 1210 can correspond to anembodiment of operation 1020. Operation 1215 can include the wirelesscommunication device 302 determining a displacement vector, D,representing a displacement direction and displacement magnitude ofmobility of the wireless communication device 302 during the OOScondition. D can, for example, be determined from satellite navigationsystem positioning data, location data, accelerometer data, somecombination thereof, or the like, as described above. Operation 1215 canfurther include the wireless communication device 302 determiningwhether D exceeds a Δthreshold having a corresponding displacementdirection. In this regard, operation 1215 can correspond to anembodiment of operations 1030 and 1040. If it is determined in operation1215 that D> Δthreshold, then the method can proceed to operation 1220,which can include the wireless communication device 302 selecting andusing an aggressive scan mode. Operation 1220 can accordingly correspondto an embodiment of operation 1050. If, on the other hand, it isdetermined in operation 1215 that D≦ Δthreshold, then the method caninstead proceed to operation 1225, which can include the wirelesscommunication device 302 selecting and using a passive scan mode.Operation 1225 can accordingly correspond to an embodiment of operation1060.

Returning to operation 1205, if it is determined that location-coveragemapping information is not available, then operations 1210-225 can beomitted, and the method can proceed to operation 1230 illustrated inFIG. 12B. Operation 1230 can include the wireless communication device302 selecting to use a statistical mode and setting a scalardisplacement threshold, d_(threshold). The scalar displacement thresholdcan, for example, be set based on a rate of degradation of a receivedsignal quality prior to the OOS condition. In this regard, operation1230 can correspond to an embodiment of operation 920. Operation 1235can include the wireless communication device 302 determining adisplacement magnitude, D, indicative of a distance traveled by thewireless communication device 302 during the OOS condition. Thedisplacement magnitude can, for example, be determined from satellitenavigation system positioning data, location data, accelerometer data,some combination thereof, or the like, as described above. Operation1235 can further include the wireless communication device 302determining whether D is greater than d_(threshold). Operation 1235 canaccordingly correspond to an embodiment of operations 930 and 940. In aninstance in which it is determined at operation 1235 thatD>d_(threshold), the method can proceed to operation 1240, which caninclude the wireless communication device 302 selecting and using anaggressive scan mode. Operation 1240 can accordingly correspond to anembodiment of operation 950. If, on the other hand, it is determined inoperation 1235 that D≦d_(threshold), the method can instead proceed tooperation 1245, which can include the wireless communication device 302selecting and using a passive scan mode. Operation 1245 can accordinglycorrespond to an embodiment of operation 960.

The various aspects, embodiments, implementations or features of thedescribed embodiments can be used separately or in any combination.Various aspects of the described embodiments can be implemented bysoftware, hardware or a combination of hardware and software. Thedescribed embodiments can also be embodied as computer readable code ona computer readable medium for controlling manufacturing operations oras computer readable code on a computer readable medium for controllinga manufacturing line. The computer readable medium is any data storagedevice that can store data which can thereafter be read by a computersystem. Examples of the computer readable medium include read-onlymemory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, andoptical data storage devices. The computer readable medium can also bedistributed over network-coupled computer systems so that the computerreadable code is stored and executed in a distributed fashion.

In the foregoing detailed description, reference was made to theaccompanying drawings, which form a part of the description and in whichare shown, by way of illustration, specific embodiments in accordancewith the described embodiments. Although these embodiments are describedin sufficient detail to enable one skilled in the art to practice thedescribed embodiments, it is understood that these examples are notlimiting; such that other embodiments may be used, and changes may bemade without departing from the spirit and scope of the describedembodiments.

Further, the foregoing description, for purposes of explanation, usedspecific nomenclature to provide a thorough understanding of thedescribed embodiments. However, it will be apparent to one skilled inthe art that the specific details are not required in order to practicethe described embodiments. Thus, the foregoing descriptions of specificembodiments are presented for purposes of illustration and description.The description of and examples disclosed with respect to theembodiments presented in the foregoing description are provided solelyto add context and aid in the understanding of the describedembodiments. The description is not intended to be exhaustive or tolimit the described embodiments to the precise forms disclosed. It willbe apparent to one of ordinary skill in the art that many modifications,alternative applications, and variations are possible in view of theabove teachings. In this regard, one of ordinary skill in the art willreadily appreciate that the described embodiments may be practicedwithout some or all of these specific details. Further, in someinstances, well known process steps have not been described in detail inorder to avoid unnecessarily obscuring the described embodiments.

What is claimed is:
 1. A method for selecting an out of service (OOS)scan mode for a wireless communication device, the method comprising thewireless communication device: detecting occurrence of an OOS condition;setting a displacement threshold in response to the OOS condition;determining a displacement magnitude indicative of a distance traveledby the wireless communication device during the OOS condition;determining whether the displacement magnitude exceeds the displacementthreshold; using a first scan mode to scan for network coverage in aninstance in which it is determined that the displacement magnitudeexceeds the displacement threshold; and using a second scan mode to scanfor network coverage in an instance in which it is determined that thedisplacement magnitude does not exceed the displacement threshold, thefirst scan mode having a greater scan frequency than the second scanmode.
 2. The method of claim 1, further comprising the wirelesscommunication device: determining a rate of degradation of a receivedsignal quality prior to the OOS condition; and wherein setting thedisplacement threshold comprises setting the displacement thresholdbased at least in part on the rate of degradation of the received signalquality prior to the OOS condition.
 3. The method of claim 2, furthercomprising the wireless communication device: determining whether therate of degradation of the received signal quality prior to the OOScondition exceeds a threshold rate; and wherein setting the displacementthreshold comprises: setting a first displacement threshold in aninstance in which the rate of degradation of the received signal qualityprior to the OOS condition exceeds the threshold rate; and setting asecond displacement threshold in an instance in which the rate ofdegradation of the received signal quality prior to the OOS conditiondoes not exceed the threshold rate, wherein first displacement thresholdhas a smaller magnitude than the second displacement threshold.
 4. Themethod of claim 1, further comprising the wireless communication device:receiving, prior to the OOS condition, location-coverage mappinginformation indicative of an extent of network coverage within an areain which the wireless communication device is located; and whereinsetting the displacement threshold comprises setting the displacementthreshold based at least in part on the location-coverage mappinginformation.
 5. The method of claim 4, further comprising the wirelesscommunication device: determining a displacement direction associatedwith the displacement magnitude; and defining a displacement vectorbased at least in part on the displacement magnitude and thedisplacement direction; and wherein: setting the displacement thresholdcomprises setting a threshold displacement vector based at least in parton the location-coverage mapping information and the displacementdirection; and determining whether the displacement magnitude exceedsthe displacement threshold comprises determining whether thedisplacement vector exceeds the threshold displacement vector.
 6. Themethod of claim 1, further comprising the wireless communication device:determining, in response to the OOS condition, whether the wirelesscommunication device has access to location-coverage mapping informationfor an area in which the wireless communication device is located; in aninstance in which it is determined that the wireless communicationdevice has access to location-coverage mapping information for the areain which the wireless communication device is located, setting thedisplacement threshold comprises setting the displacement thresholdbased at least in part on the location-coverage mapping information; andin an instance in which it is determined that the wireless communicationdevice does not have access to location-coverage mapping information forthe area in which the wireless communication device is located, settingthe displacement threshold comprises setting the displacement thresholdbased at least in part on a rate of degradation of a received signalquality prior to the OOS condition.
 7. The method of claim 1, furthercomprising the wireless communication device: detecting an input to thewireless communication device after occurrence of the OOS condition; andusing the first scan mode in response to the user input.
 8. The methodof claim 1, wherein determining the displacement magnitude comprisesdetermining a first displacement magnitude at a first time, the methodfurther comprising the wireless communication device, in an instance inwhich the displacement magnitude does not exceed the displacementthreshold: determining a second displacement magnitude indicative of adistance traveled by the wireless communication device during the OOScondition at a second time, the second time being subsequent to thefirst time; determining whether the second displacement magnitudeexceeds the displacement threshold; switching to the first scan mode toscan for network coverage in an instance in which the seconddisplacement magnitude exceeds the displacement threshold; andcontinuing to use the second scan mode to scan for network coverage inan instance in which the second displacement magnitude does not exceedthe displacement threshold.
 9. The method of claim 1, whereindetermining the displacement magnitude comprises determining thedisplacement magnitude based at least in part on position informationdetermined via a satellite navigation system.
 10. The method of claim 1,wherein determining the displacement magnitude comprises determining thedisplacement magnitude based at least in part on an accelerometermeasurement.
 11. A wireless communication device comprising: atransceiver configured to transmit data to and receive data from anetwork; and processing circuitry coupled to the transceiver, theprocessing circuitry configured to control the wireless communicationdevice to at least: detect occurrence of an out of service (OOS)condition; set a displacement threshold in response to the OOScondition; determine a displacement magnitude indicative of a distancetraveled by the wireless communication device during the OOS condition;determine whether the displacement magnitude exceeds the displacementthreshold; use a first scan mode to scan for network coverage in aninstance in which it is determined that the displacement magnitudeexceeds the displacement threshold; and use a second scan mode to scanfor network coverage in an instance in which it is determined that thedisplacement magnitude does not exceed the displacement threshold, thefirst scan mode having a greater scan frequency than the second scanmode.
 12. The wireless communication device of claim 11, wherein theprocessing circuitry is further configured to control the wirelesscommunication device to: determine a rate of degradation of a receivedsignal quality prior to the OOS condition; set the displacementthreshold based at least in part on the rate of degradation of thereceived signal quality prior to the OOS condition.
 13. The wirelesscommunication device of claim 12, wherein the processing circuitry isfurther configured to control the wireless communication device to:determine whether the rate of degradation of the received signal qualityprior to the OOS condition exceeds a threshold rate; and set thedisplacement threshold at least in part by: setting a first displacementthreshold in an instance in which the rate of degradation of thereceived signal quality prior to the OOS condition exceeds the thresholdrate; and setting a second displacement threshold in an instance inwhich the rate of degradation of the received signal quality prior tothe OOS condition does not exceed the threshold rate, wherein firstdisplacement threshold has a smaller magnitude than the seconddisplacement threshold.
 14. The wireless communication device of claim11, wherein the processing circuitry is further configured to controlthe wireless communication device to: receive, prior to the OOScondition, location-coverage mapping information indicative of an extentof network coverage within an area in which the wireless communicationdevice is located; and set the displacement threshold based at least inpart on the location-coverage mapping information.
 15. The wirelesscommunication device of claim 14, wherein the processing circuitry isfurther configured to control the wireless communication device to:determine a displacement direction associated with the displacementmagnitude; define a displacement vector based at least in part on thedisplacement magnitude and the displacement direction; set thedisplacement threshold at least in part by setting a thresholddisplacement vector based at least in part on the location-coveragemapping information and the displacement direction; and determinewhether the displacement magnitude exceeds the displacement threshold atleast in part by determining whether the displacement vector exceeds thethreshold displacement vector.
 16. The wireless communication device ofclaim 11, wherein the processing circuitry is further configured tocontrol the wireless communication device to: determine, in response tothe OOS condition, whether the wireless communication device has accessto location-coverage mapping information for an area in which thewireless communication device is located; in an instance in which it isdetermined that the wireless communication device has access tolocation-coverage mapping information for the area in which the wirelesscommunication device is located, set the displacement threshold based atleast in part on the location-coverage mapping information; and in aninstance in which it is determined that the wireless communicationdevice does not have access to location-coverage mapping information forthe area in which the wireless communication device is located, set thedisplacement threshold based at least in part on a rate of degradationof a received signal quality prior to the OOS condition.
 17. Thewireless communication device of claim 11, wherein the processingcircuitry is further configured to control the wireless communicationdevice to: detect an input to the wireless communication device afteroccurrence of the OOS condition; and use the first scan mode in responseto the user input.
 18. A computer program product for selecting an outof service (OOS) scan mode for a wireless communication device, thecomputer program product comprising at least one non-transitory computerreadable storage medium having computer program code stored thereon, thecomputer program code comprising: program code for detecting occurrenceof an OOS condition; program code for setting a displacement thresholdin response to the OOS condition; program code for determining adisplacement magnitude indicative of a distance traveled by the wirelesscommunication device during the OOS condition; program code fordetermining whether the displacement magnitude exceeds the displacementthreshold; program code for using a first scan mode to scan for networkcoverage in an instance in which it is determined that the displacementmagnitude exceeds the displacement threshold; and program code for usinga second scan mode to scan for network coverage in an instance in whichit is determined that the displacement magnitude does not exceed thedisplacement threshold, the first scan mode having a greater scanfrequency than the second scan mode.
 19. The computer program product ofclaim 18, further comprising: program code for determining a rate ofdegradation of a received signal quality prior to the OOS condition; andwherein the program code for setting the displacement thresholdcomprises program code for setting the displacement threshold based atleast in part on the rate of degradation of the received signal qualityprior to the OOS condition.
 20. The computer program product of claim18, further comprising: program code for receiving, prior to the OOScondition, location-coverage mapping information indicative of an extentof network coverage within an area in which the wireless communicationdevice is located; and wherein the program code for setting thedisplacement threshold comprises program code for setting thedisplacement threshold based at least in part on the location-coveragemapping information.